<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>

    body{
       
        background-color:firebrick;
        display: inline-block;

    }
</style>
<body  background-color:fas;>
    <div class="linear-gradient" >
        <button id="fafa" onclick="fafa()">生成</button>
        <button id="fdsafdsa">改变</button>
    </div>

    <script>    
function fafa(){
    let a = document.getElementsByTagName("body");
    console.log(a.style);

    


}




    </script>
</body>
</html>